Video: Building Blocks of the SR 99 Tunnel

How to build a highway in a tube

August 22, 2016

Seattle's Alaskan Way Viaduct Replacement program, featuring Bertha the hardest working tunneling machine in the business, does everything in a big way. This Washington State Department of Transportation video shows how the curved segment building blocks of the tunnel were formed as precast segments at Encon Washington from start to finish.